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Stabilized Etchant Formulation for Wet Silicon Etching

IP.com Disclosure Number: IPCOM000115182D
Original Publication Date: 1995-Mar-01
Included in the Prior Art Database: 2005-Mar-30
Document File: 2 page(s) / 22K

Publishing Venue

IBM

Related People

Linde, HG: AUTHOR [+2]

Abstract

An antioxidant additive for silicon etchant formulations is described that prolongs the life of the etchants. Formulations of ethanolamine, gallic acid and water that are used to micromachine silicon suffer from oxidation and lose their effectiveness when exposed to oxygen. If 0.5% to 10% (by weight based on the weight of gallic acid) of ascorbic acid is added to a formulation, it acts as an antioxidant and stabilizes the formulation. Ascorbic acid consumes the oxygen within the etch container since it is more susceptible to oxidation than gallic acid. The ascorbic acid is sacrificed to prolong the useful life of the formulation.

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Stabilized Etchant Formulation for Wet Silicon Etching

      An antioxidant additive for silicon etchant formulations is
described that prolongs the life of the etchants.  Formulations of
ethanolamine, gallic acid and water that are used to micromachine
silicon suffer from oxidation and lose their effectiveness when
exposed to oxygen.  If 0.5% to 10% (by weight based on the weight of
gallic acid) of ascorbic acid is added to a formulation, it acts as
an antioxidant and stabilizes the formulation.  Ascorbic acid
consumes the oxygen within the etch container since it is more
susceptible to oxidation than gallic acid.  The ascorbic acid is
sacrificed to prolong the useful life of the formulation.